Field of the Invention
The technique disclosed in the present specification relates to a Group III nitride semiconductor light-emitting device.
Background Art
The semiconductor light-emitting device is a device to extract light emitted from the light-emitting layer to the outside. To efficiently extract the light emitted from the light-emitting layer, a light extraction surface is often formed at an interface between the device and the outside. Techniques of forming an unevenly shaped portion on the light extraction side of the substrate or forming an unevenly shaped portion on a surface of conductive oxide film such as ITO have been developed.
For example, Patent Document 1 discloses a semiconductor light-emitting device having a second cladding layer on which an unevenly shaped light extraction structure is formed (see FIG. 6 of Patent Document 1). This technique improves the light extraction performance (see paragraph [0010] of Patent Document 1).
Patent Document 1: Japanese Patent Application Laid-Open (kokai) No. 2012-33695
As disclosed in Patent Document 1, the unevenly shaped portion on the light extraction surface has recesses and protrusions appearing alternately. However, light extraction performance may be further improved by providing more complicated irregularities.